A A Analysis of the individual DBC Items of the autistic relating sub-scale

There was no significant difference on the autistic relating sub-scale score between the RS Child and the Autism group. It is possible that the total score for the autistic relating sub-scale is made up differently for the RS Child and Autism group. To investigate which behaviours contributed to the same level of scoring on the sub-scale, the profile of scoring on the eleven individual items was investigated. Table 7.2.4:c shows the percentage of individuals in the RS Child and Autism group (males and females) reported to show each of the eleven items. Mann-Whitney U tests were used to confirm whether there was a significant difference between the RS Child and the Autism group. The percentage of SLD girls who did not have a diagnosis of autism reported to show each of the eleven items is also presented in Table 7.2.4:c. The reason for including this group was to compare the frequency of these behaviours in the RS Child group to that in a group of girls with severe to profound learning disabilities without a diagnosis of autism (according to parent report). Mann-Whitney U tests were used to compare the RS Child group to this group of girls with SLD who did not have a diagnosis of autism. To make it easier to examine the differences between groups, the percentage of individuals in each group rated as showing each of the behaviours is presented in Figure 7.2.4:b

Five of the individual items were rated significantly higher in the RS than in the Autism group: “repeated movements”, “facial twitches”, “unhappy”, “under active” and “sleeps too much”. These individual items were also rated higher in the RS group than in the group of girls with SLD without a diagnosis of autism except for “sleeping too much” where there was no difference. It appears that these behaviours were associated more with RS than autism or severe learning disability.

Three of the individual items were rated higher in the Autism group than in the RS group: “aloof, “avoids eye contact” and “doesn’t respond to others feelings”. Just one of these behaviours, “aloof, was also rated higher in the

RS group than in the group of SLD girls without autism. The other two behaviours (“avoids eye contact” and “doesn’t respond to others feelings”) were rated with similar frequency in the RS and the SLD group without autism. It seems the behaviours “avoids eye contact” and “doesn’t respond to others feelings” were associated more with autism than RS or severe learning disability.

Three behaviours were rated with the similar frequency in the RS and the Autism group: “resists being cuddled”, “laughs for no reason” and “doesn’t show affection”. These three items were rated significantly higher in the RS than in the SLD girls without autism. It appears that these behaviours were associated with autism and RS rather than SLD.

Table 7.2.4:c Individual items of the Autistic relating sub-scale - RS girls vs. sub-sample of children with a diagnosis of autism; RS girl n=130 Autistic n=32 Mann-Whitney RS vs. Autistic SLD not autistic n=67 Mann-Whitney RS vs. SLD not autistic ITEM % cases item true % cases item true u _P % cases item true u _P Repeated movements of hands, body or head

93.1 71.9 1347.5 <.001 20.9 821.0 <.001

Facial twitches 71.5 34.4 1215.5 <.001 14.9 1772.5 <.001

Unhappy 63.1 34.4 1567.5 .015 28.4 2858.5 <.001

Underactive 60.0 25.0 1344.0 .001 41.8 3222.0 .001

Sleeps too much 28.5 3.10 1548.0 .002 16.4 .812.5 .056

Aloof 69.3 96.9 1110.5 <.001 53.7 3617.0 .032

Avoids eye contact 44.6 90.6 963.5 <.001 37.3 4077.5 .405

Doesn’t respond to others feelings

55.4 81.3 1611.0 .036 28.3 3188.5 .001

Resists being cuddled 30.8 46.9 1710.0 .061 26.9 4151.0 .498

Laughs for no reason 93.9 93.8 1730.0 .095 47.7 1841.0 <.001

Doesn’t show affection 35.3 37.5 1974.0 .596 12.0 3383.0 .001

Figure 7.2.4:b Individual items of autistic relating sub-scale 100 RS Girl □ Autistic SLD not autistic A® *0 AO

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r

To determine the effect of physical ability and gender on the ratings of the individual items of the autistic relating sub-scale, a number of logistic regression analyses were carried out. In these analyses, group (RS vs. Autism, or RS vs. SLD not autistic) was entered as the dependent variable. Physical ability and gender were entered as predictor variables in the first step of the regression. The DBC item was then entered as a predictor variable at the second step of the regression. This was done to determine whether the item could discriminate between the groups once physical ability and gender had been taken into account. Table 7.2.4:d shows the results of the regression analyses.

Once physical ability and gender had been controlled for, none of the autistic relating sub-scale items could differentiate between the RS and the Autism group. Once physical ability had been taken into account, all except three of the autistic relating items could discriminate between the RS and SLD group, showing the behaviours were more frequent in the RS group. The three items that could not discriminate between the girls RS and girls with SLD without

autism were “sleeps too much”, “aloof, and “avoids eye contact”. The results indicate that these three behaviours are related to severe learning disabilities in general rather than RS or autism, whereas the other eight behaviours are related to RS and autism rather than severe learning disabilities.

Table 7.2.4:d Logistic regression analysis on individuals items of autistic relating sub-scale

RS vs. SLD RS vs. SLD not autistic

ITEM OR* 95% 01 for

_P

_P

OR OR

Repeated movements of hands, 9.42 .5 5 -1 6 2 .3 4 2.24 .123 13.92 6 .8 7 -2 8 .1 8 2.63 <.001 body or head

Facial twitches 3.35 .51 -2 1 .8 5 1.21 .207 6.67 3 .3 8 -1 3 .1 5 1.90 <.001

Unhappy .48 .07 - 3.45 -.73 .469 2.89 1 .5 6 -5 .3 7 1.06 .001

Under active 1.11 .2 4 -5 .1 2 .10 .895 1.78 1 .1 4 -2 .7 7 .58 .011

Sleeps too much 1004 .0 0 - 1095 6.91 .916 1.37 .74 - 2.55 .32 .313

Aloof .07 .00 - 2.33 -2.60 .139 1.61 .98 - 2.66 .48 .061

Avoids eye contact .45 .07 - 2.69 -.83 .373 1.22 .7 5 -1 .9 7 .20 .423

Doesn’t respond to others feelings .25 .0 3 -1 .9 8 -1.38 .190 1.97 1 .2 6 -3 .1 0 .68 .003 Resists being cuddled 2.42 .25 - 22.94 .88 .442 2.02 1 .0 3 -3 .9 6 .70 .041 Laughs for no reason 2.56 .1 6 -3 9 .8 4 .94 .503 5.48 3 .1 0 -9 .6 9 1.70 <.001 Doesn’t show affection .12 .01 - 2.54 -2.14 .173 3.62 1 .5 7 -8 .3 7 1.29 .003 *Odds ratio = p(RS Child group) / p(aut or SLD group)

7.2.4.5 Summary of comparison o f RS Child with autism group

• On the autistic relating sub-scale girls with RS scored at the same level as the group of children with a diagnosis of autism according to parental report.

• Before accounting for differences in physical ability and gender, the RS group showed a different profile of scoring on the 11 individual items of the scale compared to those with a diagnosis of autism.

• Once physical ability and gender were taken into account, none of the 11 autistic relating items could differentiate between girls with RS and children with a diagnosis of autism. This implies that the different profile of scoring on the items seen in the RS and the autistic group was accounted for by differences in physical ability and gender.

• Eight of the 11 items differentiated between girls with RS and girls with SLD without autism. Thus, the reason why RS girls were rated the same as the autistic children on these eight items was unlikely to be related to their severe level of learning disability.

• There were three items where the girls with RS, children with autism and girls with SLD looked similar. This suggests that these particular items were related to level of learning disability rather than to autism or RS. • In order to follow-up the question of the association between RS and

autism a second study was carried out. See chapter 10 for the background, method, and results of this second study.